1 This publication brings together a number of related series of statistics on demography including estimated resident population (ERP), births, deaths, migration, marriages and divorces. For details of publication of other data related to demography, see paragraph 42.

2 As a result of an amendment made in 1992 to the Acts Interpretation Act, 1901-1973(Cwlth), the Indian Ocean Territories of Christmas Island and the Cocos (Keeling) Islands have been included as part of geographic Australia, hence another category of the state and territory classification has been created. This category, known as Other Territories, includes Christmas Island, the Cocos (Keeling) Islands and Jervis Bay Territory. Population, births, deaths and overseas migration data for Australia shown in table 1.1 includes Other Territories.

POPULATION

3 This section consists of ERP, with information on overseas arrivals and departures, interstate migration and population and household projections.

Population estimates

4 The concept of ERP links people to a place of usual residence within Australia. Usual residence is that place where each person has lived or intends to live for six months or more in a reference year.

5 The ERP is an estimate of the Australian population obtained by adding to the estimated resident population at the beginning of each period the components of natural increase (on a usual residence basis) and net overseas migration. For the states and territories, account is also taken of the estimated interstate movements involving a change of usual residence. After each census, estimates for the preceding intercensal period are revised by incorporating an additional adjustment (intercensal discrepancy) to ensure that the total intercensal increase agrees with the difference between the ERPs at the two respective census dates.

6 ERPs are based on census counts by place of usual residence, to which are added the estimated net census undercount and Australian residents estimated to have been temporarily overseas at the time of the Census. Overseas visitors in Australia are excluded from this calculation.

8 Population projections are published twice in each intercensal period. The latest projections are based on the results of the 1996 Census of Population and Housing and relate to the period 1999-2101.

9 The population projections are not intended as predictions or forecasts; they are illustrations of growth and change in the population which would occur if certain specified assumptions about future demographic trends were realised. The projections are based on a combination of assumptions for future levels of births, deaths and migration to arrive at the size, structure and distribution of Australia's population into the next century.

10 Series I assumes an annual net overseas migration gain of 110,000 from 2001-02, high net internal migration gains and losses for states and territories, and that the total fertility rate remains at 1.75 births throughout the projection period. Series II assumes an annual net overseas migration gain of 90,000 from 2001-02, medium net internal migration gains and losses for states and territories, and that the total fertility rate declines to 1.6 births per woman by 2008, and then remains constant. Series III assumes an annual net overseas migration gain of 70,000 from 2001-02, low net internal migration gains and losses for states and territories, and that the total fertility rate declines to 1.6 births per woman in 2008, and then remains constant. All series assume a constant mortality assumption. The 1986-1996 rate of improvement in life expectancy of 0.30 years per year for males and 0.22 years per year for females continues until 2001-2003 and then gradually declines, resulting in life expectancy at birth of 83.3 years for males and 86.6 years for females in 2051. After this it remains constant until 2101. For state and territory specific assumptions refer to Population Projections, 1999 to 2101 (cat. no. 3222.0).

Household projections

11 Household projections are estimates of future numbers of households based on assumptions about changing living arrangements of the population, and illustrate what would happen to the number and type of households in Australia if recent trends were to continue over the 25-year projection period (1996-2021). Household projections are not predictions or forecasts.

12 The ABS uses a propensity method to project numbers of households, which identifies propensities (proportions) from the Census of Population and Housing for people in each five-year age group to be living in different living arrangement types. Trends observed in the propensities over the last three censuses are then projected forward and applied to the projected population. From these projections of living arrangements, numbers of households are derived.

13 Three projection series are produced, based on three different assumptions about the rate of change in the propensity to belong to different living arrangement types. All series use the same projected population. Series A assumes no change; the living arrangement propensities remain constant to 2021. Series B assumes a low rate of change, in which the linear trend in propensities from 1986 to 1996 continues at the full rate of change to 2001, then continues at half the rate of change to 2006, at one-quarter the rate of change to 2011 and then remains constant to 2021. Series C assumes that the 1986-1996 rate of change in propensities continues at the full rate of change to 2021. For a more detailed explanation of the methods and assumptions used see Household and Family Projections, Australia, 1996-2021 (cat. no. 3236.0).

BIRTHS

14 Data presented in this publication refer to births registered during the calendar year shown. There is usually an interval between the occurrence and registration of a birth, and, as a result of delay in registration, some births occurring in one year are not registered until the following year, or even later. However, most births are registered soon after they occur. More than 99% of births occurring in one year are registered by 30 June of the following year.

15 Birth statistics are presented on the basis of the state or territory of usual residence of the mother, regardless of where in Australia the birth occurred or was registered.

16 Births to mothers usually resident in Australia which took place overseas are excluded. Births to mothers usually resident overseas which occurred in Australia are included in the state or territory where the birth occurred.

DEATHS

17 Data presented in this publication refer to deaths registered during the year shown. There is usually an interval between the occurrence and registration of a death, and as a result some deaths are not registered in the year in which they occur. However, most deaths are registered within six months of occurrence. More than 99% of deaths occurring in one year have been registered by 30 June of the following year.

18 Death statistics are presented on the basis of the state or territory of usual residence of the deceased, regardless of where in Australia the death occurred or was registered.

19 Deaths which occurred in Australia of persons usually resident overseas are included in these statistics and are classified according to the state or territory in which the death was registered. Deaths of Australian residents which occurred overseas are not included.

Life tables

20 Australian 1999-2001 life tables are based on three years of population and deaths data to reduce the impact of year-to-year statistical variations in the age-specific death rates. Age-specific death rates are further graduated by actuarial methods. Life tables for the states and territories are produced on the same principles.

Small area life tables

21 Expectation of life for statistical divisions and subdivisions (table 4.6) have been calculated with reference to state and territory life tables, using Brass' Logit System. Small area life tables are based on age-specific death rates for each area, some of which may be zero as no deaths were recorded at those ages. Brass' Logit technique enables the calculation of smooth abridged life tables for regions which have defective age-specific death rates, by adjusting them with reference to a standard life table. The technique does not alter the overall level of mortality, but the age-specific functions of the life tables are smoothed.

22 Essentially, the technique compares mortality between the regional and standard life tables across ages, then a line of best fit is calculated to describe that relationship by age. The line of best fit is then used in conjunction with the standard life table to determine mortality rates for the small area life table. For a more detailed description of Brass' Logit System refer to Brass (1975): Methods for Estimating Fertility and Mortality from Limited and Defective Data.

Causes of death

23 For deaths registered from 1999 onwards, the tenth revision of the World Health Organisation's International Classification of Diseases (ICD-10) has been used for the coding of causes of death. Causes of death descriptions and corresponding codes used in this publication, therefore, relate to particular causes or groups of causes as classified in ICD-10. The introduction of ICD-10 has broken the underlying cause of death series, particularly at the more detailed level of classification. For information on the differences between ICD-9 and ICD-10, please refer to the 1999 issue of Causes of Death, Australia(cat. no. 3303.0).

24 The time-series summary table (table 4.1) includes causes of death data. Deaths registered prior to 1999 are coded on the ninth version of the World Health Organisation's International Classification of Diseases (ICD-9), while data from 1999 onwards is coded to ICD-10 and is therefore not directly comparable with previous years presented in the table. Data from 1999 onwards in this table relates to:

Neoplasms (C00-D48)

Diseases of the circulatory system (I00-I99)

Diseases of the respiratory system (J00-J99)

Diseases of the digestive system (K00-K93)

All other diseases (remainder of A00-T98)

External causes (V01-Y98)

from the ICD-10 classification.

MIGRATION

Overseas migration

25 Data from passenger cards completed by persons arriving in or departing from Australia, together with other information available to the Department of Immigration and Multicultural and Indigenous Affairs (DIMIA), serve as a source for statistics on overseas migration.

26 Data relate to the number of movements of travellers rather than to the number of travellers. However, the statistics exclude the movements of operational air crew and ships' crew, transit passengers who pass through Australia but are not cleared for entry, and passengers on pleasure cruises commencing and finishing in Australia.

27 The estimates from July 1976 onwards include an adjustment for the net effect of category jumping. This adjustment is necessary because net permanent and long-term migration figures can be affected by changes in travel intentions from short-term to permanent/long-term or vice versa. Prior to December quarter 1989, adjustments for category jumping were only made to revised population estimates. These adjustments are now included in preliminary estimates. For further details see Demographic Estimates and Projections: Concepts, Sources and Methods.

28 There have been delays in the receipt of final Overseas Arrivals and Departures data from August 2000 onwards from DIMIA, therefore complete overseas migration component data for 2000 and 2001 is not yet available.

29 In the absence of this data, an estimate of net overseas migration for 2001 has been assumed using a projection consistent with the medium assumption for net overseas migration included in Population Projections, Australia, 1999 to 2101 (cat. no. 3222.0), while category jumping for the September and December quarters 2000 has been set to zero.

Interstate migration

30 Data on interstate migration have been derived from aggregated statistical information on interstate changes of address advised to the Health Insurance Commission in the process of administering Medicare. The ABS adjusts the Health Insurance Commission data to make allowance for the number of persons who do not inform the Commission of their change of residence. Further details are available in Demographic Estimates and Projections: Concepts, Sources and Methods.

MARRIAGES

31 Marriage statistics refer to marriages registered by the Registrar of Births, Deaths and Marriages of WA during the years shown. There is usually an interval between the celebration and the registration of a marriage. As a result of the delay in registration, some marriages celebrated in one year are not registered until the following year. Under the Marriage Act 1961(Cwlth), marriages may be celebrated by a minister of religion registered as an authorised celebrant, by a district registrar or by other persons authorised by the Attorney-General. Notice of the intended marriage must be given to the celebrant at least one calendar month, and within six calendar months, before the marriage. A celebrant must transmit an official certificate of the marriage for registration to a District Registrar in the state or territory in which the marriage took place.

32 In 1973, the minimum age at which a person may marry without parental consent was reduced from 21 to 18 years, although women were legally free to marry from 16 years with parental consent. Further amendment to the Marriage Act in 1991 designated the minimum age at which both sexes are legally free to marry to be 18 years. Persons between the ages of 16 and 18 years may marry with parental or guardian consent and an order from a judge or magistrate. Any two persons under the age of 18 years may not marry each other.

DIVORCES

33 All divorce data in this publication are for state or territory of registration, based on the location of the Family Court where the divorce was granted and registered. Due to the large number of divorces granted in the ACT where usual residence was in another state, the rates for the ACT are not representative of the ACT population. The number of divorces shown for the ACT is dependent on the number of cases heard by the Family Court in the ACT. As there is no residential requirement under Family Law, applicants may be resident anywhere in Australia.

34 Under the Family Law Act 1975(Cwlth), the only ground on which a divorce may be granted is that of irretrievable breakdown of the marriage. This ground is established by the husband and wife having lived apart for 12 months or more, and there being no reasonable likelihood of reconciliation. Application for nullity of marriage under Family Law legislation must be on the ground that there was a failure to meet a legal requirement, such as that neither party be already lawfully married to another person. There is no provision for judicial separation under Family Law legislation.

35 Successful applicants for a divorce are initially granted a decree nisi. This becomes absolute after one month, unless it is rescinded or appealed against, or the Family Court is not satisfied that proper arrangements have been made for the welfare of any children involved.

36 The statistics shown in this publication are compiled by the ABS from information supplied by the Family Court in respect of each application which resulted in the granting of a decree absolute.

37 In the interpretation of data, it is important to bear in mind that the availability of judges and the complexity of the cases brought before them can affect the number of decrees granted or made absolute in any one year. A rise in numbers may reflect only the clearing of a backlog of cases from an earlier period.

INDIGENOUS BIRTHS AND DEATHS DATA

38 The coverage of Indigenous births and deaths is affected by the extent to which people are identified as Indigenous. Propensity to identify (the likelihood that a person will identify or be identified as Indigenous) is determined by a range of factors, including who completes the administrative form for registering a birth or death (e.g. a parent, a relative, or an official); the perception of how the information will be used; education programs about identifying as Indigenous; and emotional reaction to identifying as Indigenous. Estimates of the extent of the coverage of Indigenous births and deaths are shown in table 3.1 and table 4.1 respectively. For further details see Births, Australia (cat. no. 3301.0) and Deaths, Australia (cat. no. 3302.0).

GEOGRAPHIC BOUNDARIES

39 The geographic boundaries used in this publication are defined in the Australian Standard Geographical Classification (ASGC) 2001 (cat. no. 1216.0).

ACKNOWLEDGMENT

40 ABS publications draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated: without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905(Cwlth).

SUPPRESSION OF SMALL CELLS

41 For all data in this publication, cell values with small values have been suppressed to assist in the preservation of confidentiality of information.

43 AusStats is a web based information service which provides the ABS full standard product range on-line. It also includes data in multidimensional datasets in SuperTABLE format, and time series spreadsheets.

44 As well as the statistics included in this and related publications, additional information is available from the Demography Theme Page on this site.

45 Current publications and other products released by the ABS are listed in the Catalogue of Publications and Products(cat. no. 1101.0). The Catalogue is available from any ABS office or this site. The ABS also issues a daily Release Adviceon this site which details products to be released in the week ahead.

46 Appendix 1 lists characteristics processed by the ABS for population, births, deaths, migration, marriages and divorces. For more information about these statistics refer to the contact details supplied in the Inquiries Box at the front of this publication.